Projector-lamp.



J. W. KELLOGG.

PROJECTOR LAMP.

.APPLIOATION FILED JULY 24. 1908.

Patented Feb. 1, 1910.

Inventor Witnesses:

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UNITED STATES, PATENT OFFICE.

JAMES W. KELLOGG, OF SCI-IENECTADY, NEW YORK, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PROJECTOR-LAMP.

To all whom it may concern:

Be it known that 1, JAMES W. KELLooe, a citizen of the United States,residing at Schenectady, in the county of Schenectady, State of NewYork, have invented certain new and useful Improvements in Projector-Lamps, of which the following is a specification.

This invention relates to electric arc lamps for projectors, in whichthe electrodes are arranged preferably in a horizontal position, with afeed screw for each electrode. The two screws are geared together in theproper ratio to keep the arc at the focus of the projector, and arerevolved by an actuator, such as a pawl, engaging with a driving wheel,such as a ratchet wheel, on one of them, the pawl being actuated by anelectromagnet in shunt to the arc.

My invention has for its object the automatic separation of the carbonswhen starting the arc, or when, in operation, the arc voltage dropsbelow normal. I accomplish this by providing another electromagnet andactuator operating to turn the feed screw in the opposite direction tothat in which the feeding-together magnet revolves it. This reverse orfeeding-apart magnet is held normally out of circuit by an electromagnetin shunt to the arc; said magnet permitting a closure of the circuit ofthe feeding-apart magnet only in case the arc voltage is below normal.

The accompanying drawing is a diagrammatic illustration of a projectorembodying my invention, the lamp and feed screws being shown as if swungaround into the plane of the ratchet wheel.

The electrodes 1 2 are carried in holders 3 4, which are fed togetherand apart by feed screws 5 6 connected by the gears 7 8. On one of saidscrews is a driving wheel, such as the ratchet wheel 9 which can bedriven in a direction to feed the electrodes toward each other, by meansof a spring-actuated pawl 10 carried by the armature lever 11 of thefeeding-together electromagnet 12. In the drawing the wheel and pawl areshown broken ofi' from the feed screw and turned to a position at rightangles to that in which they really stand, in order to show them inelevation instead of edge view. A spring 13 urges the armature lever 11away from the magnet 12, and closes the circuit thereof at the contacts14; said magnet being in shunt Specification of Letters Patent.

Application filed July 24, 1908.

Patented Feb. 1, 1910. Serial No. 445,080.

! to the arc. The tension of the spring 13 is adjusted to overcome thepull of the magnet when the drop across the arc is normal, so that thepawl remains in the position shown, with its tail 15 against the stop 16and its nose out of engagement with the ratchet wheel. But when the arclengthens to a point where its resistance compels an abnormal fiow ofcurrent through the magnet winding, the tension of the spring isovercome and the armature moves downward; the pawl sliding over theteeth of the ratchet wheel. This action, however, breaks the circuit ofthe magnet at 1A, which deencrgizes the magnet and permits the spring topull 1 up the armature, and at the same time causes the pawl, which hashooked into a tooth of the ratchet, to turn the wheel clockwise and feedthe carbons together. This vibration of the armature continues so longas the drop across the arc is greater than normal, and the result isthat the electrodes are fed toward each other to compensate for theirconsumption, until the resistance of the are once more becomes normal.In case, however, the voltage drop across the electrodes becomes lessthan a predetermined amount, owing to their getting too close, or eventouching, as will be the case when the lamp is to be started, there is anecessity for some device to separate them. Such a device is the subjectof this present invention. It consists of an electromagnet 17 connectedacross the line, with its armature 18 mounted on a lever 19, which isconnected with the lever 20 on which is pivoted a spring-actuated pawl21 having a tail 22. A stop 23 cooperates with said tail and acts todisengage the pawl from the ratchet wheel when said armature lever isdown. A spring 24 is arranged to lift said lever and cause the pawl 21to actuate the wheel in a reverse direction from that produced by thepawl 10.

In order to keep the reversing pawl 21 out of engagement with the wheelduring the operation of the feedingtogether magnet an electromagnet 25is arranged to act upon the lever 19, said magnet 25 being in shunttothe arc and in parallel with the magnet 12. The tension of the spring 2%is less than that of the spring 13, so that the lever 19 will be pulleddown by the magnet 25 while the resistance of the ark remains at orabove normal. The magnet 25, therefore, keeps the pawl 21 inactiveduring the normal operation of the lamp; But when the arc voltage dropsso low that the magnet 25 is overcome by the spring 24, the parts assumethe position shown in the drawing, the pawl 21 rising, pushing vtheratchet wheel over in a counterclockwise direction and feeding apart theelectrodes. This movement of the armature lever, however, closes thecircuit of the magnet 17 at 26 and the energizing of this magnet by thefull line voltage causes it to pull down the lever 19 and engage thepawl with another tooth of the ratchet. As the downward movement of thelever breaks the circuit of the feeding-apart magnet 17, the spring 24again lifts the lever, giving the feed screws another backward impulse,whereby the electrodes are fed apart still farther. This actioncontinues until the electrodes have been separated far enough to throwsuiiicient current through the magnet 25 to enable it to retain thelever 19 in its downward position once more. By the automatic operationof these magnets and actuators acting upon the driving wheel and turningthe feed screws forward or backward, as the case may be, the lamp isstarted and kept burning in an efficient and satisfactory manner.

that I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. A projector having geared feed screws,

- a driving wheel on one of said screws, a

feeding-together actuator and a feedingapart actuator adapted to engagewith said wheel, an electromagnet in a normally closed circuitcontrolled by said electromagnet for operating the feeding togetheractuator, an electromagnet in a normally open circuit for operating thefeeding-apart actuator, and an electromagnet in shunt to the are forkeeping the circuit of the feedingapart actuator open while the arcvoltage is at or above normal.

2. A projector having geared feed screws, a. driving wheel on one ofsaid screws, 2. feeding-together actuator and a feedingapart actuatoradapted to engage with said wheel, an electromagnet in shunt to the arc,an armature lever for said magnet connected to the feeding-togetheractuator and controlling the circuit of said magnet, an electromagnetconnected across the line and having an armature lever connected to thefeeding-apart actuator and also controlling the circuit of saidelectromagnet, and a third electromagnet in shunt to the arc and actingupon the same armature lever as the feedingapart magnet.

3. A projector having geared feed screws, a driving wheel on one of saidscrews, a feeding-together actuator and a feedingapart actuator adaptedto engage with said wheel, an electromagnet in shunt to the arc, anarmature lever for said magnet connected to the feeding-togetheractuator and controlling the circuit oi said magnet, an elec tromagnetconnected across the line and having an armature lever connected to thefeeding-apart actuator and also controlling the circuit of saidelectromagnet, a third electromagnet in shunt to the arc and acting uponthe same armature lever as the feedingapart magnet, and springs attachedto said armature levers and acting in opposition to their respectivemagnets, the spring for the feeding-together magnet being the stronger.

In witness whereof, I have hereunto set my hand this 22nd day of July,1908.

JAMES l/V. KELLOGG. lVitnesses BENJAMIN B. HULL, HELEN ORFORD.

